[EM] Re: Blake's Margins Arguments

[Blake Cretney]

On Sun, 2003-03-02 at 20:59, MIKE OSSIPOFF wrote:

> 
> Majority matters because it's a group of people whose need for defensive 
> strategy can be minimized to a degree qualitatively better than
> can be said for a submajority group of people. As described by the
> definitions of the majority defensive strategy criteria.

That's certainly a unique way of defending majority rule.

> > That's a strategic, not a majoritarian argument.
> 
> You wanted a majoritarian argument to justify majority?

Here's my point.  Sometimes one of your arguments for wv is that it
protects the only true majorities, and that since everybody (or at least
a lot of people) believes in majority rule, we should use wv.  This is
what I call the majoritarian argument, and this is what I've been
arguing against in my recent emails.  Arguments about how wv is good at
preventing strategic voting are a different kind of argument.  I feel I
dealt with this adequately in the page I originally linked to. 
http://condorcet.org/rp/inc.shtml

> Though many agree with me that the pairwise preferences of a majority
> group matter, as a fundamental standard, it needn't be considered only
> a fundamental standard. For instance, when you violate such a majority
> preference, that can't be good for social utility. It could and often
> would result in a lowering of SU much greater than the miniscule difference 
> that margins advocates claim for margins in the questionable
> zero-info simulations that they refer to. If SU counts as a fundamental
> standard, then it's a reason to not avoidably violate majority pairwise
> preferences.

I agree that the pairwise preferences of a majority group matter.  I
even agree that the pairwise preferences of a majority group, as you
define it, matter.  I just don't agree that the majorities as you define
them should always take precedence over other majorities, as I define
them.

Furthermore, "can't be good for social utility" isn't much of an
argument.  Personally, I don't think it can be good for social utility
to favour a lower margin majority over a higher margin of majority.  So
there!

> I'd said:
> 
> >In fact, that's the usual form of the familiar lesser-of-2-evils
> >problem: A majority prefer B to A, but they're split between factions
> >who consider the middle candidate B or the nonmiddle candidate C their
> >favorites.
> 
> I think the Mutual Majority Criterion that was discussed a while back is
> a good way of viewing this problem.
> 
> I reply:
> 
> It isn't. It's about a fortuitous special case. It doesn't typically
> apply to the problem that you're referring to, the one described in
> my paragraph that you quoted above, in which the majority referred to
> don't agree that both B & C are better than C. MMC doesn't apply
> generally to the classic lesser-of-2-evils problem example.

You have a point, but as I understand it, the lesser-of-2-evils problem
isn't really solvable in a general case.  So, its really an argument
about what special cases you want to solve it for.

> Here's Blake's definition of MMC. It's reasonably right. Presumably
> he's referring to actual votes rather than sincere preferences. Plurality 
> meets MMC then, except that maybe Blake specifies that
> the criterion mustn't be applied to Plurality, so that Plurality won't
> pass. If the criterion referred to sincere preferences and stipulated
> sincere voting, Plurality would fail for the reason why we'd expect
> Plurality to fail. Likewise with Condorcet's Criterion, Smith Criterion,
> Condorcet Loser, etc. It's often said that Plurality fails Condorcet
> Loser. No it doesn't, when that criterion is defined in terms of
> actual votes.

We've had this discussion before.  I could define all the criteria in
terms of sincere votes, but this would rely on a precise definition of
what constitutes a sincere vote, possibly on a method by method basis. 
Some people argue that a sincere approval vote is one where no approved
candidate is preferred to a non-approved candidate.  Perhaps someone
believes that a sincere plurality vote is a vote for anyone other than
their least favourite candidate.

Also, it would make my definitions much different from those found in
academic literature.

---
Blake Cretney